Systems, devices and methods for the compression, expansion, and/or storage of a gas are described herein. An apparatus suitable for use in a compressed gas-based energy storage and recovery system includes a pneumatic cylinder having a working piston disposed therein for reciprocating movement in the pneumatic cylinder, a hydraulic actuator coupled to the working piston, and a hydraulic controller fluidically coupleable to the hydraulic actuator. The apparatus is fluidically coupleable to a compressed gas storage chamber which includes a first storage chamber fluidically coupleable to the pneumatic chamber, and a second storage chamber is fluidically coupleable to the first storage chamber. The first storage chamber is disposed at a first elevation and is configured to contain a liquid and a gas. The second storage chamber is disposed at a second elevation greater than the first elevation, and is configured to contain a volume of liquid.